1. Field of the Invention
The present invention relates to a method of rolling finished sections from preliminary sections by means of roll stand arrangements which operate in reversing operation. The roll stand arrangements include a compact rolling group composed of a first universal stand at the entry side and a second universal stand at the exit side and an intermediate edging stand arranged between the universal stands, and a roughing group arranged in front of the compact rolling group and composed of vertical roll stands and horizontal roll stands and/or universal stands.
2. Description of the Related Art
The rolling of sheet piling sections and angle sections and similar sections has in the past generally been carried out in fully continuously operating rolling trains, wherein the large number of shaping grooves necessary in reversing operation for the roughing rolling of such sections required great lengths of the bodies of the rolls for accommodating the number of shaping grooves. These large stands and the rolls themselves, as well as the necessary manipulating devices for introducing the rolling stock into the various grooves are very complicated, require a large amount of space and have relatively low throughput capacities. The large quantities of rolling stock lead to relatively long rolling times during reversing rolling and, therefore, they do not make it possible to operate such plants in a timed sequence with a continuous casting machine. For this reason, relatively large intermediate storage facilities are required when continuous casting plant and rolling mill are used together.
Moreover, in the case of fully continuous rolling particularly of angle steel sections and U-shaped steel sections, six or more roll stands with the appropriate drives are required because of the large number of shaping grooves.
In addition to the disadvantages described above, this leads to high costs for the large number of rolls to be made available and for exchanging and refinishing the rolls. Furthermore, in the case of discontinuous roughing rolling and the also continuous finish rolling, different temperatures over the length of the rolling stock cannot be avoided, wherein the different temperatures occur as so-called temperature wedges between the beginning and the end of the rolling length caused by the relatively low entry speed of the rolling stock into the first stand of the rolling train. These temperature wedges must be compensated or controlled in order to meet the requirements made of the rolling stock, for example, by heat treating plants. It has already been demanded to combine the production of a relatively small number of sheet piles and different angle sections with the production of girders or beams in the plants of the above-described type in which practically only girders were rolled in the past. However, since the production of girders or beams always takes place in a combined operation with a continuous casting plant, i.e., without reversing roughing stands, the combinations with a production of sheet piles and angle sections could only be realized with an extremely large number of additional devices and reassemblies.